Justice League: Chronicles Cheats - GBA

Batman: Roundhouse Kick
Press [A] ([Punch]) twice, then hold [A] the third time.

Flash: Jab
Press [A] ([Punch]) twice, then hold [A] the third time.

Green Lantern: Green Punch Fist
Press [A] ([Punch]) twice, then hold [A] the third time. John will unleash a green fist.

HawkGirl: Mace slam
Press [A] ([Punch]) twice, then hold [A] the third time. Shyera will unleash a mace slam move.

Martian Manhunter: Psychic Energy Rings
Press [A] ([Punch]) twice, then hold [A] the third time. . Jonn-Jozz will unleash energy rings.

Superman: Uppercut
Press [A] ([Punch]) twice, then hold [A] the third time.

Wonder Woman: Hook Punch
Press [A] ([Punch]) twice, then hold [A] the third time.

Play as Martian Manhunter
Complete all three story modes (Dark Winter, Trial In Ape City, Savage Time) to unlock Jonn-Jozz in the Watchtower Combat Simulator.

Raining enemies
In Savage Time, make sure you have a superhero that flies (not Flash or Batman). After the Superman Zeppelin bonus level, make your way through the interior castle, to the second bridge (the wooden platforms with soldiers walking). Make sure your hero is on the bridge, then press [Up]x3 time to fly. Fly up the screen and keep pressing [Up] to hear punching sound effects. Soldiers will fall down your screen; because your hero is hitting enemies off your screen view. Note: Your hero will only stay in the air for five to six seconds before landing. Note: You must have a flying Justice League hero, in order for this trick to work.

Hold objects
Press [B] near an object then [B] again to lift and throw the object. The same thing can be done on enemies when they are stunned.

Unlock Jonn-Jozz
Complete all three story modes.